Comparison of the inhibitory effects of conbercept and ranibizumab on corneal neovascularization in rats

Objective To compare the inhibitory effect of subconjunctival injection of conbercept and ranibizumab on corneal neovascularization (CNV) in rats. Methods A total of 72 SPF male SD rats were randomly divided into four groups including normal control group(12 rats), model control group(20 rats), ranibizumab group (20 rats)and conbercept group(20 rats). CNV formation was induced by alkali burn in the model control group, ranibizumab group and conbercept group, which received subconjunctival injection of 0.05 ml normal saline, 0.5 mg (0.05 ml) ranibizumab, or 0.5 mg (0.05 ml) conbercept on the day of modeling, respectively. At 4, 7 and 14 days after modeling,the anterior segment photos of the eyes were captured by slit lamp microscope and the area of CNV was calculated. The structure of the corneal tissue was detected by hematoxylin-eosin (H-E) staining and the microvessel density(MVD) was observed by immunohistochemical CD34-positive (CD34⁺) staining. On the 14th day after modeling, Western blot and quantitative real-time PCR (qRT-PCR) were used to observe the expression of vascular endothelial growth factor (VEGF) and vascular endothelial growth factor receptor 2 (VEGFR-2) protein and mRNA. Results The CNV area of the ranibizumab group and conbercept group was smaller than that of the model control group (P<0.05) at 4, 7 and 14 days after the establishment of the model, and there was no significant difference in CNV area between the ranibizumab group and conbercept group (P>0.05). H-E staining showed that the degree of corneal stromal edema, CNV count and inflammatory cell infiltration were alleviated in the ranibizumab group and conbercept group compared with the model control group at 4,7 and 14 days after modeling. The results of immunohistochemical CD34⁺ staining showed that the MVD in the ranibizumab group and conbercept group was less than that in the model control group (P<0.05), but no statistically significant difference was found between the ranibizumab group and conbercept group(P＞0.05). Western blot and qRT-PCR results showed that the expression of VEGF and VEGFR-2 protein and mRNA in the ranibizumab group and conbercept group were lower than that of the model control group (P<0.05). Conclusions Subconjunctival injection of ranibizumab or conbercept have equivalent effects on CNV in rats, and ranibizumab or conbercept can reduce the expression of VEGF and VEGFR-2.